View IDs topic,java code error

[God_Of_Destruction66]

Wat should i change in my java code​:pensive:

[Jay_M]

Change line 18 to TextView textView = (TextView) findViewById(R.id.mainTextView1);

Capital I on Id Java is case sensitive so Id isn’t the same as Id

[Shafiqul]

TextView textView = (TextView) findviewbyid(R.id.mainTextView1);

[Shafiqul]

Would you please help me? How shall I solve this?

[Nonone]

After the line MainActivity extends Activity add
private TextView textview